package com.hls.core.interceptor;

import com.hls.core.utils.IPUtils;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.jetbrains.annotations.NotNull;
import org.springframework.stereotype.Component;
import org.springframework.util.CollectionUtils;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.List;

@Slf4j
@Component
public class AuthorityIPInterceptor extends HandlerInterceptorAdapter {

    //@Value("#{'${ip.allowed}'.empty?null:'${ip.allowed}'.split(',', -1)}")
    private List<String> apiAllowed;

    @Override
    public boolean preHandle(
            @NotNull HttpServletRequest request,
            @NotNull HttpServletResponse response,
            @NotNull Object handler)
            throws Exception {
        // 过滤ip,若用户在白名单内，则放行
        String ipAddress = IPUtils.getRealIP(request);
        log.info("USER IP ADDRESS IS => " + ipAddress);

        if (CollectionUtils.isEmpty(apiAllowed)) {
            return true;
        }
        if (StringUtils.isBlank(ipAddress)) {
            response.getWriter().append("<h1 style=\"text-align:center;\">Not allowed!</h1>");
            log.info("USER IP ADDRESS IS => " + ipAddress + ",Not allowed!");
            return false;
        }
        for (String ipSection : apiAllowed) {
            if (ipAddress.equals(ipSection) || ipIsValid(ipSection, ipAddress)) {
                return true;
            }
        }
        response.getWriter().append("<h1 style=\"text-align:center;\">Not allowed!</h1>");
        log.info("USER IP ADDRESS IS => " + ipAddress + ",Not allowed!");
        return false;
    }

    public static boolean ipIsValid(String ipSection, String ip) {
        if (ipSection == null) {
            throw new NullPointerException("IP段不能为空！");
        }
        if (ip == null) {
            throw new NullPointerException("IP不能为空！");
        }
        ipSection = ipSection.trim();
        ip = ip.trim();
        final String REGX_IP =
                "((25[0-5]|2[0-4]\\d|1\\d{2}|[1-9]\\d|\\d)\\.){3}(25[0-5]|2[0-4]\\d|1\\d{2}|[1-9]\\d|\\d)";
        final String REGX_IPB = REGX_IP + "-" + REGX_IP;
        if (!ipSection.matches(REGX_IPB) || !ip.matches(REGX_IP)) {
            return false;
        }
        int idx = ipSection.indexOf('-');
        String[] sips = ipSection.substring(0, idx).split("\\.");
        String[] sipe = ipSection.substring(idx + 1).split("\\.");
        String[] sipt = ip.split("\\.");
        long ips = 0L, ipe = 0L, ipt = 0L;
        for (int i = 0; i < 4; ++i) {
            ips = ips << 8 | Integer.parseInt(sips[i]);
            ipe = ipe << 8 | Integer.parseInt(sipe[i]);
            ipt = ipt << 8 | Integer.parseInt(sipt[i]);
        }
        if (ips > ipe) {
            long t = ips;
            ips = ipe;
            ipe = t;
        }
        return ips <= ipt && ipt <= ipe;
    }
}
